This invention relates to a multi-poised condensing furnace and, in particular, to a secondary condensing heat exchanger for use in a multi-poised furnace.
The term multi-poised furnace, as herein used, refers to a furnace that can be orientated so that conditioned return air leaving the furnace may be discharged in either an upward or downward direction, as well as horizontally both to the left or to the right, without modifications to the furnace. Some furnaces are presently available that allow the unit to be installed in different positions, however, for the most part, these units require extensive modifications to achieve the desired result.
High efficiency furnaces extract most of the available energy from the flue gases and as a result any moisture found in the flue gas products will be reduced to condensate while the gases are in the heat exchanger of the furnace. Typically, the multi-poise furnace is equipped with a primary heat exchanger which partially receives high temperature flue gases from a burner and transfers a high percentage of the available energy to the return air. The partially cooled gases are then passed to a secondary condensing heat exchanger designed to further extract energy from the gases to a level wherein condensate is formed. If the condensate is permitted to collect in the secondary heat exchanger, the exchanger surface can corrode rapidly leading to an early failure of the unit. By the same token, if condensate is permitted to build up in the exchanger the efficiency, and thus the performance of the furnace, will be adversely effected.